Propeller-wheel.



No. 833,850. YATENTED 00123, 1906. v

LN. R. SMITH.

PROPELLER WHEEL. I uruonmn rmm inn 1o, 190s. 1

' 2 SHEETS-SHEET 1.

[NI/EN TOR Nam/7R5??? I 1 Y A TORNEY I PATENTED OCT. 23, 1906 N. B. SMITH.

PROPB-LLER WHEEL. Arrmunxox nun mm; 10. 1905.

Norma R 5 272, 75

I ATTO NE! INVEN TOR teracted bv UNITED STATES PATENT OFFICE.

NORMAN B. SMITH, or SEATTLE, WASHINGTON:

I PROPELLER-WHEEL.

No. 833,850. Specification of Letters Patent. Patented'Oct. 23, 1906.

. Application filed July 10,1905. Serial No. 269,117.

of Washington, have invented certain new and useful Improvements in Propeller-Wheels, of which the following is a specification.

My invention relates to an improvement in propeller-wheels, and .comprises the features which will be hereinafter pointed out in the claims.

r The object of my invention is to produce a wheel having a high efficiency, and particularlyfor use at high speeds, and otherwise to improve upon the usual type'of wheels.

. The drawings illustrate my invention in the form which now seems to me best adapted to carry out the principles thereof.

Figures 1, 2, 3, and 4 are side views of my wheel, taken in different positions. Fig. 5 is an end view of the wheel in the position shown in 'Fig. 1 and of the end which is toward Fig. 5. Fig. 6 is an end view of the wheel in the position shown in Fig. 2 and of the end which is toward Fig. 6. Fig. 7 is a perspective view of the wheel. Fig. 8 is a diagram illustrating the thickness of one of the wheelwebs taken on about a middle radius.

In propeller-wheels as usually constructed there is a considerable centrifugal tendency developed which tends to discharge the water radially, which tendency is not counanything inherent in 'the wheel construction. a

By my'invention I provide a feature of construction which tends to more or less perfectly counteract this centrifugal tendency and also makes it possible to efficiently employ a broader bladethat is, one extending through a greater portion of the helixand also of a shape capable of being efficiently operated at higher speeds.

I have shown the blades as extending through a distance corresponding with half a turn of the helixthat is, half the pitch length of the screw. It is not, however, essential that this proportion be maintained. I have shown this proportion for the reason that it is favorable to illustrating my invention.- I g Referring first to Fig. 6, which is a rear endfview, it will be seen that the outer por-. "tion of the blade-surface is concave, as shown at 1, Figs. 6 and 7'. This blade-surface curves away from a radius and toward the direction of revolution, the curve being grad- .driving or backing surfaces 8.

ual and regular, continuing to the end of the blade, thus forming a cup-like surface, which tends when the wheel is rotated to draw the water inward or toward the center. On the side of the wheel which is used in forward running this cup-like shape extends throughout the width of the blade. This is the side 2. This scoop or cup-like sh ape produces an inward drawing or suction action from beyond the periphery of the blades,which adds to the volume of water which passes through the screw. In connection with the above I have also used a varying pitch for the forward driving-surface 2, the helix at the forward portion 4 being of less pitch than at the rear end 5. This variation in pitch is very clearly seen upon comparing the various figures.

' VVhile-I prefer to make the forward driving-surface 2 of increasing pitch from front to rear, I prefer to maintain as nearly a constant pitch as is practicable for the rearward I do not, however, think it desirable that the front end of the blades should have the broad flat surfaces which. a complete adherence to this would produce, and therefore round back the forward portions of the backing-surfaces as is shown-at 7, thus producing a narrow edge to the forward ends of the blades. This narrow edge does not produce the disturbance in the water and the consequent drag and resistance in running forward which would be produced if the end of the blade were left square, as is shown at the rear end. Y The rear end of the wheel has been modified in shape by drawing the central portion down to a thin or relatively thin edge, as is shown in Fig. 6. The central hub is drawn down at 8, so as to merge into the web. This increases the area of the space within the periphery of the blades which is available for conducting away the water acted upon by the wheel.

The cupping of theblade-surfaces at 1 makes a wide outer edge, which if unmodified would mean a considerable mass of metal. 'I therefore prefer to reduce this by forming a groove or valley 6, extending from the point where the outer edge widens to the rear.

varies in thickness reason of the different pitches used for opposite surfaces. This igure is a diagrammatic projection of a sec- The diagram Fig. 8 shows how the web tion throughout the length of a web takenabout half-way from the hub to the periphery. The straight line represents a constant pitch and the curved line the variable pitch. The curve 7 represents how the constant-pitch surface is departed from at the forward end of the Wheel in order to avoid the wide end on the blade.

By the construction described I get the advantage of an increasing-pitch wheel for forward running and avoid much of the disadvantage of an increasing pitch when reversing. The inwardlycurved. or scooplike shape of the blade-surface at 1 holds the water within the outline of the wheel and, in fact, draws in additional water, whereby the additional water required by an increasingpitch wheel is supplied, and also the wheel may be run at a higher speed without throwing the water outward or racing when near the surface.

The cavitation effect produced is always parallel and in line with the shaft, and. the consequent or resultant of the force applied to the Water is in line with the shaft. This form of wheel when properly designed may be turned at high speed with the shaft horizontal and the wheel just submerged without showing any material centrifugal effect or raising water above the surface. The entire discharge appears to be to the rear. In fact, an inward suction is produced at the side of the wheel.

It can be seen, more particularly in Figs. 1, 4, and 7, that the forward portion of the backing surface, which otherwise is a concave surface, has changed into a convex sur face 7. This change is gradual, one merging into the other. This is done largely to cut down the size of the blades at their front edges where they enter the water when running forward. This reduces the friction, but is not so necessary for the rear edges of the wheel as it would be used backing; but a very small proportion of the time and a small less of pfliciency for this little time are not materia Having thus described my invention,

what I claim, and desire to secure by Letters Patent, is

- 1. A propeller-wheel having blades extending through a material portion of its pitch length, the outer portion of one side face of the blades being concavely curved throughout the greater portion of its length, said surface at one end of the wheel reversing to a convex curve.

2. A propeller-wheel having one side of the blades of increasing pitch from the front to the rear and the other side mainly of uniform pitch, the pitches of the two sides being equal near the middle of the width of the blades.

3. A propeller-wheel having the outer portions of its blades curving forward or in the direction of turning and having the rear portion of its hub tapering to a wedge which. merges with the blades.

' 4. A propeller-wheel having one side of the blades of increasing pitch and the other side mainly of uniform pitch, said last-mentioned side having its forward portion bcveled or rounded. back to meet the surface of the opposite side.

5. A propeller-wheel having one side of the blades of increasing pitch from the front to the rear and the other side mainly of uniform pitch, the pitches of the two sides being equal near the middle of the width of the blades and the forward portion of the surface of uniform pitch being rounded over toward the opposite surface to produce a narrow front edge.

6. A propeller-wheel having blades with one side face of increasing pitch from front to rear and the other face of substantially constant pitch, the side faces of both surfaces of the blades, from a point near the hub to their outer ends, curving concavely or away from the helical planes passing through their bases and at a constantly-increasing angle.

7. A propeller-wheel having blades with one side face of increasing pitch from front to rear and the other side face of substantially constant pitch, both side faces curving from near the hub to their outer endsmoncavely or away from the helical planes passing through their bases and at an angle progressively increasing outwardly, and the rear end of the hub tapering to a wedge which merges with the blades.

8. A propeller-Wheel having blades with one side face of increasing pitch from front to rear and the other face of substantially constant pitch, the side faces of both sur faces of the blades curving concavely and away from a radius at a co]istantly-increasing angle from a point near the hub to their outer end and also having an exterior groove or valley extending along the end edges of the blades between the side surfaces.

In testimony whereof I have hereunto aflixed my signature, this 3d day of July, 1905, in the presence of two witnesses.

NORMAN R. SMITH.

Vitnesses I'IENRY L. REYNoLns, PAUL A. TALBOT. 

